If someone had already had the H1N1 flu virus, are they immune to it or can they get it a second time?

“Yes, they are immune if they’ve had it once, but only a small percentage of people have laboratory confirmation and that is the only way to be sure that you’ve had it,” said Maggie Thompson, director of communications for the Kansas Department of Health and Environment. “Unless the case was confirmed in a laboratory, individuals should plan to get the H1N1 vaccine when made available next month.”